The Doctah is a tv term related to Scifi Brit series, Doctor Who. Whooligans use this word because the pronounciation of "the Doctor" especially by the Tenth and the Eleventh became "scottish", so to joke on it they say Doctah.
When a friend is so addicted to Dota they cannot stop playing and are unable to communicate with other human beings. Solution: Addiction therapies and medication.